Projection optical system and projector apparatus

a technology of projection optical system and projector, which is applied in the direction of projectors, mountings, instruments, etc., can solve the problems of not easy to provide a system with a design, and achieve the effects of reducing the movement distance of the first focus lens group, suppressing interference, and easy suppressing fluctuations in image formation performan
US9785043B2Active Publication Date: 2017-10-10NITTO OPTICAL CO LTD
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Patent Information

Authority / Receiving Office
US · United States
Patent Type
Patents(United States)
Current Assignee / Owner
NITTO OPTICAL CO LTD
Publication Date
2017-10-10

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Abstract

A projection optical system (2) projects from a DMD (7) on a reducing side onto a screen (9) on an enlargement side, and includes: a first refractive optical system (10) that forms a first intermediate image (51) on the enlargement side using light incident from the reducing side; a second refractive optical system (20) that forms the first intermediate image (51) on the reducing side into a second intermediate image (52) on the enlargement side; and a first reflective optical system (30) including a first reflective surface (31a) with positive refractive power that is positioned on the enlargement side of the second intermediate image (52), wherein the second refractive optical system (20) includes a first focus lens group (61) that moves when focusing is carried out, and the first focus lens group (61) includes at least one lens (L13) included in the second refractive optical system (20).
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Description

TECHNICAL FIELD

[0001] The present invention relates to a projection optical system of a projector apparatus.BACKGROUND ART

[0002] Japanese Laid-Open Patent Publication No. 2004-258620 (hereinafter “Document 1”) discloses the realization of a projection optical system which, in addition to using an image forming optical system including a reflective surface to increase the size on the screen of projected images while reducing the projection space outside a projector apparatus, is capable of correcting chromatic aberration and also an image projecting apparatus that uses such projection optical system. To do so, Document 1 discloses that a first and second optical system are disposed in that order from a light valve on the projection side of the light valve, the first optical system includes at least one refractive optical system and has positive refractive power, the second optical system includes at least one reflective surface with refractive power and has positive refractive power, a...

Claims

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